The present invention relates to semiconductor spatial light modulators and, more particularly, to such modulators having multiple quantum well layers in which the modulation is effected by birefringence in the multiple quantum well layers.
Spatial light modulators (SLMs) are extensively used in the optical data/image processing technology which is vital for the realization of advanced image processing, telecommunications and computing systems. They utilize the inherent parallel processing capability of photonic systems and can be addressed electrically or optically to produce the desired signal outputs. Some of the signal processing functions performed by SLMs are optical matrix multiplication, incoherent image to coherent image conversion, electrical-to-optical conversion, thresholding of analog images, implementation of optical neural networks, and optical cross-bar switches.
SLM structures utilizing various physical effects have been reported in the literature and include liquid crystal devices and multiple quantum well modulators using quantum confined Stark effect (QCSE). Multiple quantum well (MQW) modulators and SLMs appear at present to be the fastest devices which can be addressed both electrically and optically. Recently, a new class of multiple quantum well optical modulators have been proposed in which the optical modulation is achieved by manipulation of the polarized light by field dependent birefringence in the MQW layers. The polarization-sensitive birefringent spatial light modulators (BSLMs) are in contrast with conventional multiple quantum well SLMs and with structures based upon self electrooptic device (SEED) which generally utilize quantum confined Stark effect (QCSE) to cause amplitude modulation by varying the electroabsorption.
It is an object of the present invention to provide a novel spatial light modulator based upon birefringence in a multiple quantum well structure.
It also an object to provide such a modulator which can be operated either electronically or optically.
Another object is to provide such a modulator which may be fabricated and operated relatively simply.
A further object is to provide a novel method for spatial light modulation using birefringence of polarized light in a multiple quantum well structure.